The present invention relates generally to circuit board connectors and, more particularly to a circuit board connector that uses flexible circuitry to effect a connection to a printed circuit board.
The power requirements of many chips and other integrated circuits have increased over the years. Current microprocessors and ones under development operate at very high speeds and require more power to operate at their peak efficiency. In the past, such microprocessors have been mounted directly to a circuit board, typically the mother board of a computer or other electronic device. In these applications, voltage regulators and power components have been mounted on the circuit board in proximity to the microprocessors. This type of arrangement takes up valuable real estate on the circuit board. In other arrangements, a microprocessor may be mounted on a circuit card or an insertable and removable module that plugs into a connector mounted on the main circuit board (the mother board). In these type applications, the microprocessor is inserted in a connector and the card itself is inserted into a computer. The use of connectors raises the inductance and resistance of the overall system.
Most circuit board connectors in the art utilize through-hole pins or surface mount tails to provide a connection, rather than flexible circuitry, in which the pitch of the contacts can be effectively controlled and which can provide a heat sink for power connections. When connectors are used that rely solely upon stamped and formed terminals that are soldered to circuit boards, the resistance and inductance of the connector system tends to increase. As these factors increase, so does the total impedance of the connector system. A need therefore exists, especially in chip module applications, for a connector with reduced bulk resistance and inductance, that results in a lower connector system impedance.
The present invention is therefore directed to an improved connector that has a reduced inductance and resistance compared to the prior art.
Accordingly, it is an object of the present invention to provide an improved connector for that requires no solder connections, and has better thermal properties and a lower bulk resistance than connectors presently available in the prior art.
A further object of the present invention is to provide a connector for connecting a processor module to a circuit board, the connector having a housing for receiving an edge of the module circuit board and having one or more extents of flexible circuitry that are held in contact with conductive pads on the module circuit board and which mimic the profile of the insertion edge of the circuit board.
A still further object of the present invention is to provide a connector having a housing that encloses and supports three spring members to which are mounted three discrete extents of flexible circuitry, each having contact and portions that are disposed within the connector housing in opposition to respective power, signal and ground contact pads disposed on a module circuit board, whereby the flexible circuitry provides lower bulk resistance and an improved inductance for the connector.
Yet another object of the present invention is to provide a connector for use in providing a connection between a processor module and another circuit board, in which the connector includes a housing having a slot disposed therein to receive the end of a circuit board therein, the circuit board being the substrate of the processor module, a multi-part circuit card-engaging assembly being held within the housing, the card-engaging assembly including three contact spring members, each spring having a flat body portion that terminates in a spring arm, each contact spring supporting an extent of flexible circuitry thereon, two of the springs being held together as an assembly by a first mating bar, the remaining spring being held within a second mating bar, the first and second mating bars being engageable with each other so that the spring arms of the springs support the flexible circuity within the housing on opposite sides of a centerline of the insertion slot, for engagement with airways of conductive pads disposed on the circuit board.
Still another object of the present invention is to provide a connector with a contact assembly module that is insertable into a housing of the connector, the contact assembly having at least a pair of contact arms that are adapted to engage contact pads of a circuit board on opposite surfaces of the circuit board, the contact arms being formed as approximate mirror images of each other and each having a stepped body portion so that the contact arms cooperatively define a circuit board-securing cavity that emulates the configuration of the circuit board edge to thereby create a low profile within the connecting interface of the connector housing to thereby provide a lower inductance for the connector.
These objects are accomplished by the unique novel structure of the invention. In an important aspect of the present invention, the connector does not utilize stamped and formed terminals to substantially eliminate compliance problems. The connector also uses flexible circuitry that eliminates solder connections for better control of the impedance of the connector and the system in which it is used.
The flexible circuitry that effects the connection with the processor module circuit board does so in a manner so that the flexible circuitry adopts a profile that is closer to the profile of the circuit board, thereby reducing the inductance of the connector. The flexible circuitry has a lower bulk resistance that formed terminals and the amount of conductive metal used with the flexible circuitry is such that the conductivity and thermal properties can be increased. This profile is accomplished by the configuration of the contact spring members, which each include a flat body portion and a curved contact head portion which are interconnected together by a stepped, or recessed portion which cooperates with another recessed portion to define a channel of the connector. The contact head portions extend inwardly from the stepped portion and protrude into the channel formed between the contact spring members. This channel receives the edge of a circuit card therein in a manner so that the edge of the circuit card preferably abuts the step between the stepped portion and the body portion of each contact spring. The flexible circuitry is supported along this stepped portion so that it comes as close as possible to emulating the actual profile of the edge card, thereby reducing the inductance of the connector system.
These and other objects, features and advantages of the present invention will be clearly understood through consideration of the following detailed description.